Ordinal printing mechanism with zero suppression means for calculators



Feb. 18, 1969 A. HESSE ETAL 3,427,963 ORDINAL PRINTING MECHANISM W 1TH ZERO SUPPRESSION MEANS FOR CALCULATORS Filed March 21, 1967 IN VEN T 0R5! m KW A TTORNE Y W awjim United States Patent 3 427 963 ORDINAL PRINTINGMIiCHANISM WITH ZERO SUPPRESSION MEANS FOR CALCULATORS Alfred Hesse and Alfred Keiter, Wilhelmshaven, Germany, assignors to Olympia Werke AG., W1lhelmshaven, Germany Filed Mar. 21,1967, Ser. No. 624,959 Claims priority, applicatilin Germany, Mar. 30, 1966,

I US. Cl. 101-93 10 Claims Int. Cl. B41j 5/46, 25/00 ABSTRACT OF THE DISCLOSURE Background of the invention The present invention relates to an ordinal printing mechanism for calculators, and more particularly to an ordinal printing mechanism of the type in which the printing of zeros in decimal orders above the highest order of a number is prevented.

The Swiss Patent 392,941 discloses a printing mechanism in which each type lever is connected with a hammer slide. The hammer slides of successive orders are connected by coupling projections which form a sequential connection between the hammer slides of the orders. Each hammer slide is mounted for longitudinal and pivotal movement and connected with a correlated type lever.

It is a disadvantage of the prior art construction that the hammer slides have to be mounted for movement in two transverse directions since a reliable engagement between the spring biased hammer slide and the abutment bar engaged by the same, and by the control bar which retracks the hammer slide, is not assured. Furthermore, since the hammer slides are transversely movable, they perform a fluttering motion when the respective type lever hits the platen and tends to bounce back. If the printing operation takes place at high speed, unclear imprints, or ghost imprints are produced. Furthermore, the fluttering movement of the hammer slides causes undesirable noise. Due to the fact that the hammer slides carry coupling means by which they are sequentially connected, the hammer slides have a very complex shape, and are comparatively expensive to manufacture.

Another disadvantage of this construction is that the play between the hammer slides and the respective correlated type levers is added to the play between the coupling means of the hammer slides. The resulting total play increases fluttering of the type levers and causes noise.

Summary of the invention 'printing mechanism of this type operating at a very low noise level.

Another object of the invention is to provide an ordinal printing mechanism in which printing members are sequentially coupled in a position representing the digit zero so that by blocking of the printing member of the highest order, printing of zeros above the highest order of a number is prevented.

Another object of the invention is to actuate printing members by hammers which perform a straight actuating motion.

With these objects in view, an embodiment of the invention comprises an ordinal series of hammer means movable in one direction between inoperative and operative positions and being respectively connected with an ordinal series of printing means so that each printing means moves to a printing position when the correlated hammer means moves to the operative position. Each printing means is also connected with the correlated hammer means for movement relative to the same in a second direction between a plurality of digital positions including a zero position. Each printing means has first and second coupling means disposed so that the first coupling means of each printing means in the zero position cooperates with the second coupling means of the printing means of the next lower order in the zero position to couple adjacent printing means. Stop means engage the second coupling means of the printing means of the highest order in the zero position for blocking movement of the same to the printing position so that a sequential series of printing means in the zero position down from the highest order to a lower order, whose printing means is in another digital position, is blocked against movement to the printing position. Due to the blocking of all higher printing means in zero position, no zeros are printed in an order above the highest order of a number printed by the printing means.

In accordance with the invention, the hammer means are movable in a rectilinear motion in one direction, and are preferably mounted on a pair of guides passing through straight slots in the hammer means. Due to this construction, and also due to the fact that the printing means carry the sequential coupling means, the tolerances of the movable parts arranged before the printing means can be comparatively great, since the tolerances between the coupling means of the printing means compensate for all preceding tolerances. Fluttering of the printing means due to displacement of the hammer means, and resulting ghost imprints are completely avoided. The construction of the invention performs particularly reliably, and the operation is still improved if the hammer means are guided in a stationary comb extending into the proximity of the printing means. The comb guides the hammer means laterally and prevents transverse displacement of the same.

In a preferred embodiment of the invention, the stop means which blocks movement of the printing means of the highest order in the zero positon, is preferably a portion of the comb,

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

Brief description of the drawing FIG. 1 is a fragmentary side elevation, partially in section, and illustrating one embodiment of a printing mechanism according to the invention;

FIG. 2 is a fragmentary plan view taken in the direction of the arrow II in FIG. 1; and

FIG. 3 is a fragmentary perspective view illustrating modified coupling means ofanother embodiment of the invention.

Description of the preferred embodiments Referring now to the drawing, and more particularly to FIGS. 1 and 2 illustrating one embodiment of the invention, a printing mechanism 1 is mounted on support ing means which include a pair of stationary parallel horizontal guide shafts 2 and 3 passing through elongated longitudinal slots 5 and 6 in hammers 4 which form an ordinal series. For example, ten hammers may be respectively associated with ten successive decimal orders.

Each hammer 4 has a projection 9 to which a spring 10 is secured. The other ends of springs 10 are secured to a fixed rod 10a so that all hammers 4 are biased to move to the right as viewed in the drawing until stop noses 8 engage an abutment bar which holds all hammers 4 in the illustrated inoperative position. However, when abutment bar 22 releases stop noses 8 during an operational cycle of the calculator, all hammers move to the position 4 indicated in chain lines in FIG. 1. At the end of the operational cycle, a control bar 12 is operated in the direction of the arrow a to engage a shoulder 11 of projections 9 of all hammers 4 to cock all hammers in the illustrated inoperative position abutting abutment bar 22.

An ordinal series of printing means 13, for example ten printing means 13 associated with the first ten decimal orders, is provided. Each printing means 13 is connected by pivot joint 14 with a differential actuator so that each printing means 13 can be raised and lowered between digital positions including a position representing the digit zero. FIG. 1 shows one printing means 13 in solid lines in a lower position of rest, and one printing means 13 in a higher digital position representing the digit 1. Each printing means 13 can be moved in one direction between the digital positions, but is also movable in a transverse direction to the printing position 13p in which one of its ten types 13a engages the surface of a platen 23.

Each hammer 4 is connected with the printing means 13 of the same decimal order by connecting means which permit movement of each printing means 13 between the digital positions thereof, but cause movement of each printing means to the printing position 13p when the correlated printing hammer is pulled by the respective spring 10 to its operative positon. In the illustrated embodiment, each printing hammer has a transverse projection 7 slidably disposed in an arcuate slot 16 of the respective printing means 13. The connecting means 7, 16 connect each printing means with the associated printing hammer during movement to the printing position, but permit setting of each printing means to a selected digital position while the respective hammers 4 are in the retracted inoperative position.

Each printing means has coupling means permitting a coupling of adjacent printing means. In the embodiment of FIGS. 1 and 2, each printing means 13 has a first coupling means in the form of a transverse lug or projection 18 which is formed with a cutout. Coupling projection 18 extends toward the next lower order and cooperates with a second coupling means in the form of a stud 17 which projects from each printing means 13 toward the next higher order. Coupling stud 17" of the highest order cooperates with the abutment 21 of a stop means 20 which is secured to a lateral support portion of comb 19. Coupling stud 17" is blocked by stop means 20, 21 when the corresponding printing means 13" of the highest order is in the zero position. The other cooperating pairs of first and second coupling means 18, 17 are also disposed to cooperate in the zero position of the respective printing means. However when a printing means 13 is raised to a digital position, as

shown for printing means 13', its coupling lug 17' is no longer aligned with the coupling projection 18 of the printing means of the next higher order if the latter remains in the zero position. Consequently, the respective printing means in a digital position is free to move to the printing position 13p. Assuming that the printing means 13 of all ten orders, of which only four orders are shown in FIG. 2, are in the zero position, each coupling stud 17 will abut the coupling projection 18 of the next higher order, and the coupling stud 17 of the highest order will abut stop means 21, 20, so that none of the printing means can move forward to the printing position since the coupling means 17, 18 form a chain connected with stop means 20, 21. However, if one of the printing means, for example the printing means of the eighth order is set during a calculating operation to a digital position representing a digit diiferent from zero, its coupling stud 17 will no longer be aligned with the coupling projection 18 of the ninth order, and the respective printing means 13 is free to move to the printing position, while the printing means in the ninth and tenth highest orders remain locked in the zero Position. The printing means 13 in the orders lower than the eighth of printing means 13', are also free to move to the printing position since coupling projection 18 of the eighth order has moved away from coupling stud 17 of the next lower order. In the embodiment of FIG. 3, the first coupling means is a bent lug 24 projecting towards the next lower order, and the second coupling means is a. bent lug 25 projecting toward the next higher order. Each coupling lug 25 is located behind the coupling lug 24 of the next higher order, if the respective printing means 13 are both in the same digital position, and if the respective printing means,are in the zero position, the lug 25 of the printing means of the highest order is located behind the shoulder 21 of stop means 20, so that all printing means 13 in zero positions sequentially following the printing means in the zero position are blocked and cannot move to the printing position. Raising of a printing means 13 to a digital position representing the digits from 1 to 9 will cause the respective coupling lug 25 to be located above the corresponding coupling lug 24 of the next higher order so that the respective printing means is free to move to the printing position.

In both embodiments of the invention, any printing means in an order lower than the highest order which represents a digit different from Zero, can move to the printing position although being in the zero position. For example, if printing means 13 of the eighth order is raised to a position representing the digit 1, and is consequently released for movement to the printing position, and if the printing means of the next lower seventh and sixth orders are in the zero position, the printing means of the sixth order can move to the printing position for printing a zero since printing means 13 of the seventh order, and its coupling projection 18 have advanced to the printing position after its coupling stud 17 was released by the raised projection 18 of printing means 13' moving to the printing position.

If a number is to be printed, for example a number having eight orders the highest of which has the digit 1, the printing means 13 of the eight lowest orders are raised by the respective differential actuators to positions representing the digits of the number. Coupling stud 17' is raised above coupling projection 18 of the next higher ninth order, and consequently no longer blocked by the same since the printing means of the two highest orders are held or placed in zero position. In this manner, the blocking chain formed by coupling means 17, 18 is interrupted between the eighth and ninth orders.

When the command print is given by the calculator, abutment bar 22 is raised in the conventional manner, while control bar 12 is in the position shown in FIG. 1. When stop noses 8 of all hammers 4 are released by abutment bar 22, all springs urge the hammer 4 to move to the right as viewed in the drawing so that the connecting projections 7 urge the respective printing means 13 to the printing position 13p. The printing means of the eight lower orders are moved to the printing position, but the printing means of the two highest orders cannot be displaced, since the printing means 13 of the highest order is blocked by the engagement of stop means 20, 21 by coupling stud 17', and printing means 13 of the next lower ninth order is blocked due to the engagement of its coupling stud 17 with the coupling projection 18" of the highest order. Consequently, no zeros are printed in the orders above the highest order of the number to be printed, in the present case above the eighth order.

After the printing of the number has been completed, the control bar 12 is moved in the direction of the arrow a to retract the hammers of the eight lower orders until all hammers are again locked by engagement between stop noses 8 and abutment bar 22.

In this inoperative position of hammers 4, connecting projections 7 hold the printing members aligned in a retracted position spaced from the platen 23, In order to permit a smooth operation during the setting of the printing means 13 to higher digital positions, each coupling stud 17 is spaced a small distance from the coupling projection 18 of the next higher order with which it cooperates. Therefore, the printing means of consecutive orders are slightly staggered the distance s, as shown in FIG. 2.

During a printing operation, the printing means of the highest orders in which no digit is to be printed, in the present example in the ninth and tenth orders, are also urged toward platen 23 by hammers 4. Consequently, each coupling stud 17 moves into engagement with the respec tive coupling projection 18 of the next higher order. Consequently, each printing means 13 will project the distance s beyond the printing means of the next higher order in zero position, and if the printing means of all ten orders are in zero position and a printing operation is carried out, the distances s will be added to each other, and the printing means of the lowest order will project the distance 10s beyond the printing means of the highest order. Consequently, it is necessary that the platen 23 is spaced far enough from the printing means so that the printing means of the lowest order cannot make an imprint when actuated in the zero position.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of ordinal printing mechanisms for calculators differing from the types described above.

While the invention has been illustrated and described as embodied in an ordinal printing mechanism for preventing printing of zeros in orders above the highest order of a number by coupling and blocking the printing means of the highest orders which are not used, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be protected by Letters Patent is set forth in the appended claims:

1. Ordinal printing mechanism for preventing printing of zeros in orders above the highest order of a number, comprising, in combination, an ordinal series of hammer means; guide means guiding said hammer means for movement only in one direction between inoperative and 6. operative positions; an ordinal series of printing means respectively correlated with said hammer means; connecting means connecting each printing means with the correlated hammer means for movement in said one direction so that each printing means moves to a printing position when the correlated hammer means moves to said operative position, said connecting means connecting each printing means with the correlated hammer means also for movement relative to the correlated hammer means in a second direction between a plurality of digital positions including a zero position, each printing means having first and second coupling means disposed so that said first coupling means of each printing means in said zero position cooperates with said second coupling means of the printing means of the next lower order in said zero position to couple adjacent printing means in said one direction; and stop means for engaging said second coupling means of the printing means of the highest order in said zero position for blocking movement of the same in said one direction to said printing position so that a sequential series of printing means in said zero position down from the highest order to a lower order, whose printing means is in another digital position, is blocked against movement to said printing position whereby no zeros are printed in an order above the highest order of -a number printed by said printing means.

2. A printing mechanism as claimed in claim 1 wherein each hammer means is formed with first and second straight slots extending in said one direction; and wherein said guide means include first and second stationary guide shafts respectively passing through said first and second slots for guiding said hammer means in said one direction.

3. A printing mechanism as claimed in claim 1 wherein said printing means are flat printing members, and wherein said first and second coupling means are first and second projections projecting from said flat printing members toward the higher and lower orders, respectively, said first coupling projection being located forwardly of said second projection of the printing member of the neXt lower order for blocking movement of the same in said one direction toward said printing position.

4. A printing mechanism as claimed in claim 3 wherein said first coupling projections are bent lugs, and wherein said second coupling projections are studs.

5. A printing mechanism as claimed in claim 3 wherein said first and second coupling projections are lugs bent in opposite directions toward the higher and lower orders respectively.

6. A printing mechanism as claimed in claim 1 wherein each printing means includes an elongated printing member having a plurality of types along the length thereof, and being movable in longitudinal direction between said digital positions; and means mounting each printing member for oscillating pivotal movement to and from said printing position.

7. A printing mechanism as claimed in claim 6 wherein each printing member has a longitudinally extending slot; and wherein said connecting means includes a connecting projection on each hammer means slidingly disposed in said slot of the correlated printing member for permitting relative movement between the respective printing member and hammer means, while said connecting projection angularly pivots the respective printing means to said printing position when the respective hammer means moves to said operative position.

8. A printing mechanism as claimed in claim 7 and including a spring for urging each hammer means to said operative position of the same, control means for moving said hammer means from said operative position to said inoperative position against the action of said springs, and abutment means for holding said hammer means in said inoperative position and being releasable for causing movement of said hammer means under the action of said springs to said operative position whereby said printing members are resiliently urged to said printing position.

9. A printing mechanism as claimed in claim 1 and including a comb structure for guiding said hammer means for movement in said one direction between said inoperative and operative positions, said comb structure having a. portion located in the proximity of said printing means, and wherein said stop means is a stop member mounted on said portion of said comb structure and having a shoulder cooperating with said second coupling means of the printing means of the highest order.

10. A printing mechanism as claimed in claim 1 comprising a pair of stationary guide shafts; wherein each hammer means is a fiat hammer formed with two straight slots receiving said guide shafts so that the same guide said hammers for straight movement between said inoperative and operative positions in said one direction, a spring urging each hammer to said operative position, an abutment bar for blocking all hammers in said inoperative position and being operable to release all hammers for movement to said operative position under the action of said springs; wherein each printing means includes an elongated printing member having a plurality of types along the length thereof, and being formed with a longitudinally extending slot; wherein said connecting means includes a transverse projection on each hammer guided in said slot of the correlated printing member of the same order; wherein said first and second coupling means are first and second projections projecting in opposite directions from each printing member and disposed so that the first projection of each printing member projects toward the next lower order and is located forwardly of the second projection of the printing member of the next lower order in the direction of movement toward said printing position; and wherein said stop means is a stop member located forwardly of the second coupling projection of the printing member of the highest order to block movement of the same in the zero position whereby the printing members of the following lower orders which are in zero position are also blocked by the engagement between said first and second coupling projections.

References Cited UNITED STATES PATENTS 1,812,161 6/1931 Mapel 101-93 1,951,592 3/1920 Barrett 1O193 2,100,213 11/ 1937 Garbell 101-93 2,258,091 10/1941 Ewald 101-93 2,821,909 2/1958 Grosse l01-93 2,832,283 4/ 1958 Westinger et a1 101-93 3,262,385 7/1966 Gelling 101--93 WILLIAM B. PENN, Primary Examiner. 

